Concerned for my sister and need to know if i'm over reacting?

I'm really concerned about my sisters's new found friendship. This lady is mid 50's and is a deacons wife. My sister is 27 and Sue told Tasha (my sister) that she looks at her a daughter she never had. Well she has a son that Tasha was kinda on and off with. Sue is pushing the relationship but the son really isnt into Tasha. He just got out of a serious relationship. (not the point) Sue and Tasha are going on vacation next week to Tennessee and Sue is paying for all of it. Sue booked the room for 3 days but said they might stay 5 and just pay for extra days, that she just needed a break.

Tasha and her have been going out walking every night after work, going to lounges and drinking. (shes a deacons wife) they are going walking tonight a Wednesday and Sue isnt going to church? I was taught to be faithful to church. Sue told Tasha that if she had surgery on her arm that sue would pay for it and pay her bills while she was off work. Tasha is having shoulder issues. I've tried talking to Tasha but she said everything is fine blah, blah, blah. I see so many reds flags. Whats your thoughts?